A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

In one embodiment, a method includes receiving SRS received from a plurality of UEs associated with the base station from an RU associated with the base station, estimating strengths or signal-to-noise ratios (SNRs) for pre-determined beams for each of the plurality of UEs based on the received SRS, selecting a subset of the plurality of UEs to which downlink data is to be transmitted for a RBG in a TTI based on the estimated strengths or SNRs of the pre-determined beams for the plurality of UEs, computing a precoding matrix for the RBG based on the selected subset, preparing multi-layered UE data for the RBG based on the selected subset and the computed precoding matrix, sending the multi-layered UE data and the precoding matrix for the RBG to the RU, where the RU transmits pre-coded multi-layered UE data to the UEs in the subset using MIMO technologies.

A method for transmitting a signal by device to device (D2D) user equipment (UE) supporting D2D communication, according to one embodiment of the present invention, comprises the steps of: receiving, from a base station, a message which requests reporting of the UE category of the D2D UE; and reporting the D2D UE category for a D2D operation of the D2D UE, which is set independently of the UE category for communication with the base station, wherein the D2D UE category is set on the basis of the number of fast Fourier transform (FFT) operations for asynchronous D2D links which the D2D UE can simultaneously process, and the data rate for the asynchronous D2D links which the D2D UE can process per unit time.

In one embodiment, an apparatus includes: a radio frequency (RF) front end circuit to receive and downconvert a RF signal to a second frequency signal, the RF signal comprising an orthogonal frequency division multiplexing (OFDM) transmission; a digitizer coupled to the RF front end circuit to digitize the second frequency signal to a digital signal; and a baseband processor coupled to the digitizer to process the digital signal. The baseband circuit comprises a first circuit having a first plurality of correlators having an irregular comb structure, each of the first plurality of correlators associated with a carrier frequency offset and to calculate a first correlation on a first portion of a preamble of the OFDM transmission.

A method includes obtaining a reference signal waveform (b, b.sub.1-b.sub.5) which is defined in accordance with a non-coherent modulation scheme. The method also includes—shaping the reference signal waveform (b, b.sub.1-b.sub.5) to obtain at least one signal waveform (x˜) associated with one or more subcarriers (K) of a plurality of subcarriers (301-303). The method further includes inputting the at least one signal waveform to at least one corresponding channel (1552) of a multi-channel orthogonal frequency division multiplex, OFDM, modulator (F, 1502, 1503, 1504) and transmitting an OFDM symbol (s) output by the OFDM modulator (F, 1502, 1503, 1504).

An apparatus that communicates in a mobile radio communications network, comprises signal-processing circuitry for provisioning a consecutive series of Orthogonal Frequency Division Multiplexing (OFDM) subcarriers for uplink or downlink communications; provisioning a plurality of different selectable subcarrier spacings for the consecutive series of OFDM subcarriers; performing discrete Fourier transform (DFT) coding on a plurality of data symbols to produce DFT coded symbols; and performing an inverse-DFT on the coded symbols to produce a single-carrier frequency division multiple access signal that comprises a sum of the consecutive series of OFDM subcarriers. The single-carrier frequency division multiple access signal is provided with a particular one of a set of different symbol periods by selecting one of the plurality of different selectable subcarrier spacings.

An example method of mapping a plurality of modulation symbols of a plurality of physical layer pipes present in a frame to a resource grid of data cells for the frame is described. The modulation symbols of the plurality of physical layer pipes are represented by a two-dimensional array comprising the modulation symbol values for the plurality of physical layer pipes and the resource grid of data cells is represented by a one-dimensional sequentially indexed array.

This disclosure provides systems, methods and apparatus, including computer storage media, for sidelink communications using partial symbols to reduce overhead of automatic gain control (AGC) and gaps. A transmitting user equipment (UE) maps a sidelink signal to a subset of resource elements in a frequency domain allocation defined via a comb for a first orthogonal frequency division multiplexing (OFDM) symbol. The transmitting UE performs an inverse discrete Fourier transform (IDFT) on the resource elements to generate a first time domain signal that includes a number of repetitions of a first waveform based on a structure of the comb. The transmitting UE transmits at least one repetition of the first waveform of the first time domain signal during at least a portion of the first OFDM symbol. A receiving UE performs AGC and a discrete Fourier transform on portions of the time domain signal.

There may be provided a method for priory based transmission of skywave symbols, the method may include starting to transmit a first skywave symbol; determining to stop a transmission of the first skywave symbol and to transmit a second skywave symbol that has a higher priority than the first skywave symbol; stopping the transmission of first skywave symbol before a completion of the transmission of the first skywave symbol thereby transmitting a partial first skywave symbol; and transmitting the second skywave symbol.

First and second receivers are used to receive respective first and second signals, to process said first and second signals and provide respective first and second measures thereof to respective first and second transmitters. The first and second transmitters are configured to launch the first and second measures, respectively, each comprising a desired component that has originated at a desired source, and an interference component that has originated at an interfering source. The first and/or second transmitters are configured to process and launch the respective first and second measures, properly conditioned, so that upon interception thereof by a receiving element the interference components thereof add destructively and substantially cancel (or at least partially cancel) each other, whereas the desired components avoid substantial cancellation owing to a phase relationship therebetween that differs relative to a phase relationship between the interference components.